Now, I've had this issue before. Due to problems with the department and grad studies, the woman who takes care of my salary for that job has to put in my hours manually each month. Once in a while she misses it, and she either gets a cheque cut for me, or it just ends up on my next paycheque.
So, I figured it was the same deal, and just let her know what was going on. I was surprised by the response: all "new" positions have to now be approved by the provost. First of all, my position is not new - I've been doing it for 4 years (and there were others before me). Second, why is she just telling me this now? I have a feeling that this wouldn't have even surfaced if I didn't ask her about my pay!
This isn't the first time that I've caught an issue like this - I've had problems with my department paying me less than they should pretty much every semester. Why is it that I have to make sure I get paid the right amount? You'd think with 100s of faculty/staff, they'd know how to pay people properly. I swear, they try to lowball people and just hope no one catches it :P
So, now my paycheque for this month is super low and I don't know if I'm actually going to get paid for this job anymore (and even if I am...when is it going to be approved?). Damn this university really sucks ass about things like this.